Frame structures of vehicle bodies (body shells) of automobiles are configured by numerous combinations of frame members obtained by press-molding metal plates (steel plates are taken as an example in the explanation that follows). For example, most frame members, such as side sills, cross members, and front side members have a hat shaped cross-section over some or all of their longitudinal length, formed from a top plate section, two vertical walls joined at either side of the top plate section, and two flange portions joined to the two respective vertical walls. These frame components are important components for securing crash safety in automobiles. Strengthening, to achieve a vehicle body weight reduction as well as increases crash safety performance, is strongly desired in such frame members.
FIG. 14 is explanatory diagrams of a front side member rear 4 that is a pressed article having portion curving along the longitudinal direction with a hat shaped cross-section. FIG. 14A is a perspective view, FIG. 14B is a plan view, FIG. 14C is a side view, and FIG. 14D is a cross-section diagram taken along Sec-A in FIG. 14C.
As illustrated in FIG. 14A to FIG. 14D, the front side member rear 4 has a hat shaped cross-section configured from a top plate section 2, two side walls 3, and two flange portions 1, and a curved portion in which a part of a longitudinal internal portion of the front side member rear 4 having a shape curving along the longitudinal as viewed from a side. Namely, the front side member rear 4 has a hat shaped cross-section and a curved portion with a shape curving in the up-down direction in a hill shape at the longitudinal internal portion when the molded article is disposed with the top plate section at the top side and viewed from a side face.
As described in Patent Document 1, steel stock sheet (a blank) is generally deep drawn to mold the front side member rear 4.